The book 'New Moon' doesn't tell that much about Jane and Alec. Their birthday is unknown.
January 8th Maby!
Jane Ising was born on February 2, 1902.
Jane Seymour was born on February 15, 1951.
Jane Tomlinson was born on February 21, 1964.
Jane Bowles was born on February 22, 1917.
Jane Yolen was born on February 11, 1939.
Jane Child was born on February 15, 1967.
Jane Loevinger was born on February 18, 1918.
Thomas Jane was born on February 22, 1969.
Jane Swift was born on February 24, 1965.
Jane Ising was born on February 2, 1902.
Mary Jane Croft was born on February 15, 1916.
Jane Bryant Quinn was born on February 5, 1941.